Located in Zanjan, west-central Iran, the Husseiniya is world-famous for hosting a large gathering on the eighth day of Muharram (August 6), known as the Day of al-Abbas, which is specifically allocated to Al-Abbas ibn Ali whose martyrdom was the symbol of loyalty in the battle of Karbala.

According to the Mehr news agency, the famous gathering or mourning procession of Great Hoseiniyah of Zanjan is annually participated by almost 500,000 mourners on the Day of al-Abbas who walks a distance of more than two kilometers from the Husseiniya towards the Imamzadeh Seyyed Ibrahim to display their lamentation for the Shia Imams, especially Imam Hussein (AS).

Hussainiya is a multitude hall for the mourning of Muharram and other commemoration rituals of Shia that its name gets from Imam Hussein (AS), the grandson of Prophet Muhammad (PBUH).

In this mourning procession which takes place from mid-day prayer to noon prayer, mourners in black attire show their sorrow by beating their chests in mourning to the tune of beating drums and rehearsing sad poems alongside the Maddah (eulogist) who sings the sad poems with a specific rhythm about Karbala incidents and Imam Hussein (AS).

The grandeur of this procession and the presence of hundreds of thousands of people is so great that it has never been seen anywhere in Iran. Annually, this glorious event is broadcasted live so that people around the globe can watch it through IRIB TV, foreign TV channels, and online platforms.

Being unique, the procession of the Great Husseiniya of Zanjan was registered as the country's tenth cultural and spiritual heritage in the list of cultural heritage, tourism and handicrafts on January 4, 2009.

Regarding the fact that helping the poor is a must in Islam, annually, thousands of sacrificial animals, including camels, cows, and sheep, are donated by Husseini mourners to the Husseiniya of Zanjan.

In recent years, the record of sacrificing 12,000 herds of animals by the mourners of Imam Hussein (AS) has been registered.

Regarding the huge number of sacrificial animals slaughtered by mourners in the path of the mourning procession, the Great Husseiniya of Zanjan is considered the first altar in the Shi'a world and the second altar in the Islamic world after the Mina city of Mecca during the Hajj pilgrimage.

The meat of sacrificed animals is distributed among the needy people of the province to help them with their livelihood affairs.

Every year, a huge amount of money and gold is donated by mourners and religious tourists, which is finally utilized in charity affairs such as building schools, clinics, libraries, and even creating jobs for needy people.

In Muharram 2021, a total of 4.5 billion tomans were donated by mourners to the Hoseiniyah of Zanjan, which is one of the largest centers of Shi'a Muslims in the world.

Each year, on the first Friday of Muharram, Husseiniya of Zanjan hosts many mothers who attend the ‘Hosseini infants’ ceremony in commemoration of Ali Asghar (AS), the six-month-old baby boy of Imam Hussein (AS), who was the youngest person martyred in the Battle of Karbala.

Religious ceremonies in Iran more than often include food offerings, whether they are held at public venues like mosques or private residences. These communal gatherings are also a kind of forum where friends, acquaintances, and neighbors meet over food that is served after the ceremonies. During Muharram, every village, township, city, or metropolis is abuzz with preparation for food offerings known as Nazri, the processions of which are usually sponsored by wealthy benefactors.

On the days of Tasu’a and Ashura, each neighborhood sets stands to offer food to the mourners and the passersby. Also, households provide dishes to their neighbors by distributing parcels to houses or hosting mourning ceremonies inside their homes and asking people to join by invitation.